Lecture
In the three known terms of proportion you can always find its unknown (fourth) member.
Solving proportion means finding all its members. Solve the proportion below (find x).
To find the "x", use the basic property of proportion (the rule of the "cross").
Now we are ready to understand how to solve problems in proportion.
Often tasks on proportions are closely related to percentages. Your knowledge of the percentage, you can refresh in the "Interest".
From a bow made 50 shots. 5 arrows flew past the target. Determine the hit percentage.
By tradition, we emphasize the important and numerical data in the problem.
Note that we need to determine the percentage of hits, not the percentage of arrows that have flown past.
Therefore, first we calculate how many arrows hit the target. Make it easy.
Next, to solve the problem, we will create a table where we will enter all the data. Remember that, opposite to 100%, the total amount of something is usually written in the table. Unknown percentages are denoted by x.
| Arrows | Interest | |
|---|---|---|
| Total released | 50 | 100 % |
| Hit the target | 45 | x% |
To correctly write the necessary data into a table, remember a simple rule.
Identical names need to be written under each other. Percentages are written under percents, kilograms under kilograms, etc.
Now, using the table, we will make the necessary proportion and decide it using the “cross” rule.
Answer: 90% is the percentage of hitting the target.
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Arithmetic
Terms: Arithmetic